Although the best way to save yourself from being tardy to an interview, is to make sure you’re not late in the first place.  That means mapping out your route beforehand.  Know the territory, and leave a few minutes earlier than needed.

If you cannot avoid being late, then always call ahead immediately to notify your interviewer of the situation.  You have a cell phone for a reason.  If there’s bad unexpected traffic, or an accident, call them immediately to let them know you’ll be late.  Explain the reason, apologize, and tell the interviewer that you’ll be there as quickly as possible.

When you arrive, don’t rush into the office.  Stay calm and composed.  Turn this into an opportunity to show your grace under pressure.  Being late to an interview could be considered a huge lapse in credibility.  But you can spin that by keeping your posture confident, and your demeanor positive and courteous.

By rushing in you show nervousness, which is essentially weakness.  If you crack under the stress of getting to an interview on time, are they going to want you during a real work crises?  Show that you can stay composed and confident in any scenario.

A good tactic actually is to rush as quickly as possible to the interview, then take a few moments before you enter the building to compose yourself.  The key here is staying calm, if you can’t stay calm you’re not going to make a good impression.  You’ve already got the tardiness strike against you, so your interview has to be stellar.